Bag



J. G. LEER July 26, 1966 BAG Filed June 8, 1964 United States Patent M 3,262,633 BAG Jerome G. Leer, Minneapolis, Minn., assignor to Bemis This invention relates to bags, and more particularly to open-mouth pasted-bottom paper bags.

A presently conventional type of open-mouth pastedbottom paper bag used for packaging flour, sugar and similar finely divided material in five and ten pound quantities, for example, is formed from a fiat tube having a single slit adjacent one bottom corner through both walls of the tube and a single slit adjacent the other bottom corner through both Walls of the tube defining end flaps each having a triangular section and a rectangular extension and side flaps each having a trapezoidal section and a rectangular extension. The bottom is formed by folding back one of the side flaps to turn in the end flaps, applying adhesive (paste) to the opened-up bottom, folding one of the side flaps over on a transverse fold line spaced inward from one side edge of the rectangular end flap extensions, and then folding over the other side flap on a transverse fold line spaced inward from the other side edge of the rectangular end flap extensions. In this type of bag, wherein side marginal portions of the rectangular end fiap extensions are folded over with the side fiaps, there may be a tendency for the contents of the bag (particularly in the case of packaging of materials such as flour and sugar) to sift out at the corners of the bottom, due to nonadherence between portions of the side flaps adjacent the four bottom corners of the filled bag and the end flaps resulting from the interposition therebetween of the folded-over side marginal portions of the end flap extensions.

Accordingly, among the several objects of this invention may be noted the provision of a bag of the general class above described of improved construction such as to effect adherence between portions of the side flaps adjacent the four bottom corners of the bag and the end flaps despite the folding of side marginal portions of the end flap extensions to reduce the possibility of sifting. In general, the invention involves the provision of what may be termed fringes at the side marginal portions of th end flap extensions, these fringes being folded over with the side flaps, and being such as to permit adhesive to bleed through for adherence between the portions of the side flaps adjacent the bottom corners and the end flaps. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claim.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

FIG. 1 is a view in elevation of one face of a bag tube from which a bag of this invention is made;

FIG. 2 is a view in elevation of the other face of the FIG. 1 bag tube;

FIG. 3 is an enlarged section taken on line 33 of FIG. 1, broken away to reduce the width of the view;

FIG. 4 is a view similar to FIG. 1 showing how the lower end of the bag tube is opened up in forming the bottom and how adhesive is applied; and

FIG. 5 is a view showing the completed bottom, partly broken away to show internal detail.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to the drawings, FIGS. l3 show a flat paper bag tube T from which a bag of this invention is made. This tube is usually a single-ply tube, although a multi-ply Patented July 26, 1966 bag can be made in the same way. One wall of the flat tube T is designated 1 and the other wall of the tube is designated 3. The side edges of the tube are constituted by longitudinal fold lines 5 and 7. It will be understood that the tube conventionally has a pasted longitudinal seam, but this has been omitted from the drawings to avoid unnecessary detail. Wall 3 of the tube is shown as having a tab 9 projecting centrally at its lower end.

The tube T is provided at that end (its lower end) where the bottom closure is to be formed with a first group of slits S1 adjacent on corner at said end and a second and similar group of slits S2 adjacent the other corner at said end. The slits in each group are individually designated by the reference character 11. They are cut through both walls of the tube extending inward (upward) from its lower end. The innermost slit of each group is specially designated 11a and the outermost slit of each group is specially designated 11b. Each group of slits splits up a region of the tube at its lower end into loose narrow tongues or strips 13 constituting what may be termed a fringe F.

The innermost slits 11a define two end flaps 15 for the opposite ends of the bottom closure to be formed and first and second side flaps 17 and 19. In forming the bottom closure, as shown in FIG. 4, the lower portion of the Wall 1 of the tube is folded back on a transverse fold line 21 to effect opening up of the first side flap and turning in of the two end flaps 15, with accompanying folding of wall 1 onlines 23 extending at an angle of from points 25 on the side edges 5 and 7 of the tube'to the inner ends of slits 11a in wall 1, and folding of wall 3 on lines 27 extending at an angle of 45 from points 25 to the inner ends of slits 11a in wall 3.

Each end flap 15, turned in as above described, has a triangular section as to which point 25 is the apex and a rectangular extension 29 projecting inward from the base of the triangular section. Side fiap 17 has a trapezoidal section bounded at the ends by lines 23 and a rectangular extension 31 projecting from the narrow end of the trapezoidal section. Similarly, side flap 19 has a trapezoidal section bounded at the ends by lines .27 and a rectangular extension 33 projecting from the narrow end of the trapezoidal section. Each rectangular end flap extension 29 has a fringe F at both side margins thereof, each fringe being constituted by the aforesaid narrow tongues or strips 13 which now extend transversely with respect to the tube T.

Adhesive (paste) is applied to the opened-up flaps in a pattern such as the U-shaped pattern indicated at U in FIG. 4 with the base of the U extending across extension 33 of side flap 19 and the sides of the U extending over end flap extensions 29 and the end portions of extension 31 of side flap 17. Side flap 17 is folded over on a transverse fold line 35 which is shown in FIG. 4 as generally coincident with the slits 11b in the end flap extensions 29- adjacent the upper side edges of extensions 29 to overlie the end flaps 15. Then, side flap 19 is folded over on a transverse fold line 37 which is shown in FIG. 4 as generally coincident with slits 11b in extensions 29 adjacent the lower side edges of extensions 29 to overlie the side flap 17, thereby completing formation of the bottom closure, which is designated C in FIG. 5.

As a result of the above-described operations, the bottom closure C comprises the inwardly directed end flaps 15 each having a triangular section and a rectangular extension 29 at its inner end, with first side flap 17 folded over on transverse fold line 35 to overlie the end flaps and second side flap 19 folded over on transverse fold line 37 to overlie the first side flap 17. Line 35 is spaced inward from one side edge (the upper edge as viewed in FIG. 4) of each end flap extension 29, and line 37 is spaced inward from the other side edge of each end flap extension 29. Portions of the rectangular end flap extensions 29 lying between the transverse fold lines 35 and 27 and the side edges of the extensions 29 (these side edges being defined by slits 11a) are fringed at F. The fringing F at the side margins of the end flap extensions 29 which become folded under with the side flaps 17 and 19 permits bleeding of the adhesive through the slits 11 between the tongues or strips 13 of the fringes to the inside face of the side flaps 17 and 19 for adherence between regions of the side flaps 17 and 19 such as indicated in phantom at 41 in FIG. (the regions of the fringes F) and the end flaps 15. This reduces the possibility of sifting out of the contents of the filled bag between the folded-over side marginal portions of the end flap extensions and the side flaps.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

A paper bag formed from a flat bag tube provided at one end thereof with a first group of slits through both Walls of the tube adjacent a corner of the tube at said one end of the tube and a second group of slits through both walls of the tube adjacent the other corner of the tube at said one end of the tube, the slits in each group extending inward from said one end of the tube, a portion of one wall of the tube at said one end of the tube being folded back on a transverse fold line spaced inward from the inner ends of the slits and also folded on lines extending at an' angle of 45 from points on the side edges of the tube to the inner ends of the innermost slits in said one wall, and a portion of the other wall of the tube at said one end of the tube being folded on A lines extending at an angle of from said points to the inner ends of the innermost slits in said other wall so that the bag has inwardly directed end flaps each having a triangular section and a rectangular extension at the inner end of the triangular section, and first and second side flaps, the rectangular extension of one of said end flaps having the slits of the first group at opposite side margins thereof and the rectangular extension of the other end flap having the slits of the second group at opposite side margins thereof whereby the opposite side margins of each rectangular extension are fringed, one side flap and the respective fringed side margins of the rectangular end flap extensions being folded over on a transverse :fold line spaced inward from the respective side edges of said rectangular extensions to overlie the end flaps and being adhered thereto, the other side fiap and the respective fringed side margins of the rectangular end fiap extensions being folded over on a transverse fold line spaced inward from the respective side edges of said rectangular extensions to overlie said one side flap and being adhered thereto and to the end flaps, the fringed side margins of said rectangular extensions providing for bleeding of adhesive therethrough to the portions of the side flaps overlying said fringed side margins, the side flaps being folded over on transverse lines generally coincident with the outermost slits of the groups of slits.

References Cited by the Examiner UNITED STATES PATENTS 1,029,784 6/ 1912 Appel 93-35 1,971,625 8/1928 Shively 22959 2,038,544 4/1936 Coty 22959 2,312,281 2/ 1943 Claspill et al. 22957 2,648,263 8/ 1953 Richens 9335 3,203,622 8/ 1965 F OX 22962 JOSEPH R. LECLAIR, Primary Examiner.

FRANKLIN T. GARRETT, DAVID M. BOCKENEK,

Examiners. 

